Seismic isolation apparatus for structures, method for installing apparatus thereof, and seismic isolation member

ABSTRACT

The seismic isolation apparatus  1  is an apparatus for damping the vibrations of an upper section A of a structure with respect to a lower section B of the structure, and provided with a plurality of U-shaped seismic isolation members  10,  a first coupling plate  20  to which one end of the seismic isolation member  10  is fixed, and a second coupling plate  30  to which the other end of the seismic isolation member  10  is fixed. The seismic isolation members  10 A are placed between the first coupling plate  20  and the second coupling plate  30  in a direction. The seismic isolation members  10 B are placed between the first coupling plate  20  and the second coupling plate  30  in a direction oppose to the direction of the seismic isolation members  10 A.

TECHNICAL FIELD

The present invention relates to a seismic isolation apparatus for structures, a method for installing the seismic isolation apparatus and a seismic isolation member.

This application claims priority to Japanese Patent Application No. 2007-279148 filed on Oct. 26, 2007, the content of which is incorporated herein by reference in its entirety.

BACKGROUND ART OF THE INVENTION

Conventionally, in structures such as buildings, bridges, elevated roads and elevated railways, there has been proposed a seismic isolation apparatus which is placed between an upper section such as a building frame of a structure and a lower section such as a foundation of the structure, thus damping the vibrations of the upper section to the lower section when exposed to large amounts of energy such as when earthquakes occur. For example, Patent Documents 1 to 3 below have disclosed a seismic isolation apparatus which is in combination with an isolator, and a damping mechanism between the upper section and the lower section.

In the above seismic isolation apparatus, the isolator made by alternately stacking metal plates and plate-shaped elastic bodies is interposed between the upper section and the lower section and fixed to both of them. The upper section is supported by the lower section via the isolator. A damping mechanism is constituted with a plurality of seismic isolation members (curved members) made of an elastic-plastic material. The plurality of seismic isolation members are placed regularly in the vicinity of the isolator (for example, in a radial manner), and the seismic isolation members are fixed individually, more specifically, one end thereof is fixed to the upper section while the other end is fixed to the lower section. In the damping mechanism, when large amounts of energy act on a structure by which the upper section vibrates in a horizontal direction with respect to the lower section, for example, when earthquakes occur, seismic isolation members undergo plastic deformation to absorb the seismic energy. In other words, the energy incoming to the upper section is absorbed so that the seismic isolation members can undergo plastic deformation.

-   PATENT DOCUMENT 1: Japanese Patent No. 3533110 -   PATENT DOCUMENT 2: Japanese Patent No. 3543004 -   PATENT DOCUMENT 3: Japanese Unexamined Patent Application, First     Publication No. 2004-340301

DETAILED DESCRIPTION OF THE INVENTION Problems to be Solved by the Invention

In the above-described conventional seismic isolation apparatus, the curved member as a seismic isolation member is placed parallel with a vibration direction to attain the highest energy absorption efficiency. Therefore, on the assumption that energy is incoming to the seismic isolation apparatus from all directions, it is intended that an equal seismic isolation performance is attained constantly even when the energy is incoming from some particular direction. For this reason, in designing a seismic isolation member, it is necessary to make a highly detailed evaluation. Further, as a result of the above evaluation, particular restrictions are imposed on the shape of the seismic isolation member, and the seismic isolation member must be accurately manufactured based on these restrictions so as to provide a predetermined shape.

Therefore, in the conventional seismic isolation apparatus, an excessive amount of labor is spent at the design stage and also at the manufacturing stage, resulting in an increased manufacturing cost.

The present invention has been made in view of the above circumstances, an object of which is to provide a seismic isolation apparatus for structures higher in production efficiency both at the design stage and at the manufacturing stage and lower in manufacturing cost, a method for installing the apparatus, and a seismic isolation member.

Means for Solving the Problems

In order to attain the above object, the present invention provides a seismic isolation apparatus for damping the vibrations of an upper section of a structure with respect to a lower section of the structure. The seismic isolation apparatus is provided with a plurality of U-shaped seismic isolation members, a first coupling plate to which one end of the seismic isolation member is fixed, and a second coupling plate to which the other end of the seismic isolation member is fixed. Some of the plurality of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a predetermined direction, and the other of the plurality of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a direction opposed to the predetermined direction.

In the seismic isolation apparatus of the present invention, both ends of the seismic isolation member may be fixed with bolts respectively to the first coupling plate and the second coupling plate. Each one of the bolts may be disposed at a portion by fixing one end of the seismic isolation member to the first coupling plate and a portion of the other end of the seismic isolation member to the second coupling plate, or may be disposed plurally at the respective portions. For example, three bolts are used for fixture, each of the bolts is preferably placed so as to be located at the vertex of a triangle. Further, both ends of the seismic isolation member maybe welded respectively to the first coupling plate and the second coupling plate.

In the seismic isolation apparatus of the present invention, recesses into which one end or the other end of the seismic isolation member is fitted are formed respectively on the first coupling plate and the second coupling plate, and both ends of the seismic isolation member may be fitted respectively into the recesses and fixed thereafter to the first coupling plate and the second coupling plate.

The seismic isolation apparatus of the present invention may includes an isolator having metal plates and plate-shaped elastic bodies alternately stacked. It is preferable that the isolator be placed between the upper section and the lower section.

The present invention provides a method for installing a seismic isolation apparatus having a first coupling plate to be fixed to a lower section of a structure, a second coupling plate to be fixed to an upper section of the structure opposing the lower section, and a plurality of seismic isolation members fixed respectively to the first coupling plate and the second coupling plate between the first coupling plate and the second coupling plate so as to be placed toward a predetermined direction and a direction opposing the predetermined direction, on the lower section and the upper section. This installation method includes a step of disposing the seismic isolation apparatus on the lower section so that the seismic isolation members are set along a previously assumed direction of vibrations of the upper section to the lower section, a step of fixing the seismic isolation apparatus to the lower section, a step of disposing the upper section on the seismic isolation apparatus and a step of fixing the seismic isolation apparatus to the upper section.

The present invention provides a seismic isolation member placed between an upper section and a lower section, thereby damping the vibrations of the upper section to the lower section which are generated in a previously assumed direction by its own plastic deformation. This seismic isolation member is formed in a U-shape and placed between the upper section and the lower section along the previously assumed direction of vibrations, one end of which is fixed to the lower section and the other end of which is fixed to the upper section.

In the present invention, in a case where large amounts of energy, for example, earthquakes, act on the structure including a upper section and a lower section, thereby vibrating the upper section with respect to the lower section in a direction in which seismic isolation members are placed, the seismic isolation members undergo plastic deformation so as to be displaced in a direction in which one end is spaced away from the other end, thereby consuming the energy which is incoming to the upper section. As a result, the vibrations of the upper section are damped.

According to the present invention, a direction in which vibrations are incoming is assumed previously, and the seismic isolation members are placed so as to be set along the assumed direction, thus making it possible to effectively damp the vibrations of the upper section which are generated in the assumed direction. In other words, in the present invention, since it is not assumed that energy is incoming from all directions but assumed that the energy is incoming only from a specific direction, there is no necessity for making a detailed evaluation in designing the seismic isolation members, unlike a conventional case. Further, since no particular restrictions are imposed on the shape of the seismic isolation members, there is no necessity for raising the machining accuracy of the seismic isolation members to the extent of conventional seismic isolation members.

Advantageous Effect of the Invention

The seismic isolation apparatus of the present invention is higher in production efficiency both at the design stage and at the manufacturing stage and therefore lower in manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a seismic isolation apparatus of the present invention.

FIG. 2 is a side elevational view showing the seismic isolation apparatus of the present invention.

FIG. 3 is a cross-sectional view taken along line III to III in FIG. 2 showing the seismic isolation apparatus of the present invention.

FIG. 4 is a perspective view showing a first exemplified variation of a seismic isolation member installed on the seismic isolation apparatus of the present invention.

FIG. 5 is a perspective view showing a second exemplified variation of the seismic isolation member installed on the seismic isolation apparatus of the present invention.

FIG. 6 is a perspective view showing a third exemplified variation of the seismic isolation member installed on the seismic isolation apparatus of the present invention.

FIG. 7 is a perspective view showing a first exemplified variation of a method for fixing to a coupling plate the seismic isolation member installed on the seismic isolation apparatus of the present invention.

FIG. 8 is a perspective view showing a second exemplified variation of a method for fixing to the coupling plate the seismic isolation member installed on the seismic isolation apparatus of the present invention.

FIG. 9 is a perspective view showing an exemplified variation of the seismic isolation apparatus of the present invention.

FIG. 10 is a plan view showing the exemplified variation of the seismic isolation apparatus of the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

1: SEISMIC ISOLATION APPARATUS

10, 10A, 10B: SEISMIC ISOLATION MEMBER

13, 14: BRACKET PORTION

20: FIRST COUPLING PLATE

22: COUNTER BORING (CORRESPONDING TO A RECESS OF THE PRESENT INVENTION)

24: RECESS

30: SECOND COUPLING PLATE

40: BOLT

50, 60, 70: SEISMIC ISOLATION MEMBER

A: UPPER SECTION

B: LOWER SECTION

BEST MODE FOR CARRYING OUT THE INVENTION

A description will be given of embodiments of the seismic isolation apparatus of the present invention by referring to FIG. 1 to FIG. 10.

As shown in FIG. 1 to FIG. 3, the seismic isolation apparatus 1 of the present embodiment is provided with eight seismic isolation members 10, a first coupling plate 20 to which one end 11 of each seismic isolation member 10 is fixed, and a second coupling plate 30 to which the other end 12 of each seismic isolation member 10 is fixed.

The seismic isolation member 10 is a narrow rod-shaped steel product and bent at its intermediate portion so as to give a U-shape, when viewed from the side. Bracket portions 13 and 14 greater in width than other portions are disposed respectively on two paired ends 11 and 12 of the seismic isolation member 10. The seismic isolation member 10 is similar in dimension at any portions excluding the bracket portions 13 and 14. The bracket portions 13 and 14 are disposed so as to be parallel to each other. Two through-holes (not illustrated) are formed respectively at the bracket portions 13 and 14.

The first coupling plate 20 is a rectangular-shaped steel plate uniform in thickness, and one end 11 of each seismic isolation member 10 is fixed to the upper face via a bolt 40. A bolt hole (not illustrated) into which the bolt 40 is screwed is formed on the upper face of the first coupling plate 20. A plurality of stud bolts 21, which are buried into a lower section of a structure on fixing the seismic isolation apparatus 1 of the present embodiment to the lower section, are installed upright on the lower face of the first coupling plate 20.

The second coupling plate 30 is also a rectangular-shaped steel plate uniform in thickness, and the other end 12 of each seismic isolation member 10 is fixed to the lower face via a bolt 40. A bolt hole (not illustrated) into which the bolt 40 is screwed is formed on the lower face of the second coupling plate 30. A plurality of stud bolts 31, which are buried into a upper section of the structure on fixing the seismic isolation apparatus 1 of the present embodiment to the upper section, are installed upright on the upper face of the second coupling plate 30.

Of eight seismic isolation members 10, four seismic isolation members 10A are placed at equal intervals along a side 20 a of the first coupling plate 20 and also oriented in a direction orthogonal to the side 20 a, by which one end 11 is fixed to the upper face of the first coupling plate 20 via the bolt 40. Further, these four seismic isolation members 10A are placed at equal intervals along a side 30 a of the second coupling plate 30 and also oriented in a direction orthogonal to the side 30 a, by which the other end 12 is fixed to the lower face of the second coupling plate 30 via the bolt 40.

Of eight seismic isolation members 10, four other seismic isolation members 10B are placed at equal intervals along the other side 20 b of the first coupling plate 20, in other words, along the other side 20 b parallel with the side 20 a to which the four seismic isolation members 10A are fixed, and also oriented in a direction orthogonal to the other side 20 b, by which one end 11 is fixed to the upper face of the first coupling plate 20 via the bolt 40. Further, these four seismic isolation members 10B are placed at equal intervals along the other side 30 b of the second coupling plate 30, in other words, along the other side 30 b parallel with the side 30 a to which the four seismic isolation members 10A are fixed, and also oriented in a direction orthogonal to the other side 30 b, by which the other end 12 is fixed to the lower face of the second coupling plate 30 via the bolt 40.

The four seismic isolation members 10A and the other four seismic isolation members 10B are fixed to the first coupling plate 20 and the second coupling plate 30. The seismic isolation members 10A are arranged so that curved portions of the seismic isolation members 10A are projected from between the first coupling plate 20 and the second coupling plate 30 in a predetermined direction. The seismic isolation members 10B are arranged so that curved portions of the seismic isolation members 10B are projected from between the first coupling plate 20 and the second coupling plate 30 in a direction opposite to the predetermined direction. In other words, the seismic isolation members 10A are placed in a positive direction indicated by the two-headed arrow X in FIG. 2, while the seismic isolation members 10B are placed in a negative direction indicated by the two-headed arrow X. The first coupling plate 20 and the second coupling plate 30 are placed so that all four sides are in alignment with each other when viewed from above.

The above-constituted seismic isolation apparatus 1 is disposed between the upper section A such as a building frame and the lower section B such as a foundation in the structure according to the following steps.

In the structure, for example, like a bridge girder to be placed on a bridge pier, a direction of vibrations of the upper section A to the lower section B is assumed previously. On the basis of such an assumption, first, the seismic isolation apparatus 1 is placed on the lower section B so that the seismic isolation members 10A and 10B are set along the previously assumed direction of vibrations of the upper section A (the two-way (positive/negative) direction indicated by the two-headed arrow X in FIG. 2). As described above, the stud bolts 21 are installed upright on the lower face of the first coupling plate 20 in the seismic isolation apparatus 1, and the seismic isolation apparatus 1 is fixed to the lower section B in such a manner that the stud bolts 21 are buried into the lower section B. In addition, although not illustrated, the stud bolts 21 are coupled to reinforcing steel disposed inside the lower section B, by which the seismic isolation apparatus 1 is more strongly coupled to the lower section B.

Subsequently, the upper section A is placed on the seismic isolation apparatus 1. As described above, the stud bolts 31 are installed upright on the upper face of the second coupling plate 30 in the seismic isolation apparatus 1, and the seismic isolation apparatus 1 is fixed to the upper section A in such a manner that the stud bolts 31 are buried into the upper section A. In addition, although not illustrated, the stud bolts 31 are coupled to the reinforcing steel disposed inside the upper section A, by which the seismic isolation apparatus 1 is more strongly coupled to the upper section A.

As described above, the seismic isolation apparatus 1 is disposed between the upper section A and the lower section B. In a case where large amounts of energy such as earthquakes act on the structure including the upper section A and the lower section B, thereby vibrating the upper section A with respect to the lower section B in a direction in which the seismic isolation members 10 are placed (the two-way (positive/negative) direction indicated by the two-headed arrow X in FIG. 2), the seismic isolation members 10 undergo plastic deformation so as to be displaced in a direction in which one end 11 is spaced away from the other end 12, thereby consuming the energy incoming to the upper section A. As a result, the vibrations of the upper section A are damped.

According to the seismic isolation apparatus 1, a direction in which vibrations are incoming is assumed previously, and the seismic isolation members 10 are placed so as to be set along the assumed direction (the two-way (positive/negative) direction indicated by the two-headed arrow X in FIG. 2), thereby making it possible to effectively damp the vibrations of the upper section A which are generated in the assumed direction. In other words, since it is not assumed that energy is incoming to the upper section A from all directions but assumed that the energy is incoming only from a specific direction, there is no necessity for making a detailed evaluation in designing the seismic isolation member 10, unlike a conventional case. Further, since no particular restrictions are imposed on the shape of the seismic isolation member 10, there is no necessity for raising the machining accuracy of the seismic isolation member 10 to the extent of a conventional seismic isolation member.

Therefore, production efficiency of the seismic isolation apparatus 1 can be raised both at the design stage and at the manufacturing stage, thus resulting in a lower manufacturing cost of the seismic isolation apparatus 1.

FIG. 4 shows a first exemplified variation of the seismic isolation member installed on the seismic isolation apparatus 1. A seismic isolation member 50 as the first exemplified variation is provided with one through-hole 53 for allowing a bolt 40 to pass through at a bracket portion 51 disposed at one end and one through-hole 54 for allowing a bolt 40 to pass through at a bracket portion 52 disposed at the other end. The seismic isolation member 50 is fixed to the first coupling plate 20 by using one bolt 40 and fixed to the second coupling plate 30 similarly by using one bolt 40.

In the above-described seismic isolation member 50, if each one bolt 40 is used as fixing means for the coupling plates 20 and 30, the coupling plates 20 and 30 may be fixed at a lower strength. However, in a case where vibrations act on the seismic isolation apparatus 1 in a direction other than the above-assumed direction, there is an advantage that the bolt is less likely to loosen. Further, the seismic isolation apparatus 1 is made up of a smaller number of components, thus making it possible to reduce the manufacturing cost.

FIG. 5 shows a second exemplified variation of the seismic isolation member installed at the seismic isolation apparatus 1. A seismic isolation member 60 as the second exemplified variation is provided with three through-holes 63 for allowing bolts 40 to pass through at a bracket portion 61 disposed at one end so as to be located at three vertices of a triangle and also with three through-holes 64 for allowing bolts 40 to pass through at a bracket portion 62 disposed at the other end. The seismic isolation member 60 is fixed to the first coupling plate 20 by using three bolts 40 and fixed to the second coupling plate 30 similarly by using three bolts 40.

In the above-described seismic isolation member 60, the number of bolts 40 is increased as fixing means for the coupling plates 20 and 30, thereby the coupling plates 20 and 30 can be fixed more strongly. Further, the bolts 40 are disposed so as to be located at the vertices of a triangle. Therefore, in a case where vibrations act on the seismic isolation apparatus 1 in a direction other than the assumed direction, there are advantages that the bolts are less likely to loosen as compared with a case where the coupling plates are fixed by using two bolts, and the number of the bolts is increased to reduce the size of each bolt.

FIG. 6 shows a third exemplified variation of the seismic isolation member installed on the seismic isolation apparatus 1. No through-hole for allowing a bolt to pass through is formed at bracket portions 71 and 72 disposed at both ends of a seismic isolation member 70 as the third exemplified variation. Then, one of the bracket portions, that is, the bracket portion 71, is fixed to the first coupling plate 20 by welding. In addition, although not illustrated, the other bracket portion 72 is fixed to the second coupling plate 30 by welding. There are formed beads 73 between the bracket portion 71 (or the bracket portion 72) and the first coupling plate 20 (or the second coupling plate 30).

In the above-described seismic isolation member 70, the coupling plates 20 and 30 can be fixed more strongly. Further, the seismic isolation apparatus 1 is made up of a smaller number of components, thus making it possible to reduce the manufacturing cost.

FIG. 7 is a perspective view showing a first exemplified variation of a method for fixing the seismic isolation member 10 to the first coupling plate 20 (or the second coupling plate 30) in the seismic isolation apparatus 1. In the first exemplified variation, a counter boring (corresponding to the recess of the present invention) 22 for fitting a bracket portion 13 disposed on one end 11 of the seismic isolation member 10 is formed on the side face of the first coupling plate 20 to which the seismic isolation member 10 is fixed. Then, one bracket portion 13 of the seismic isolation member 10 is fitted into the counter boring 22, with a bolt 40 allowed to pass through a through-hole 15 formed at the bracket portion 13, and fixed to the first coupling plate 20 via the bolt 40. In addition, although not illustrated, the bracket portion 14 disposed on the other end of the seismic isolation member 10 is also fitted into a counter boring formed on the second coupling plate 30, with the bolt 40 allowed to pass through a through-hole 16 formed on the bracket portion 14, and fixed to the second coupling plate 30 via the bolt 40.

In the above-described seismic isolation apparatus 1, one bracket portion 13 of the seismic isolation member 10 is fitted into the counter boring 22 formed on the first coupling plate 20 and both of them are then fixed to each other, thus making it possible to fix more strongly the first coupling plate 20 of the seismic isolation member 10. Similarly, the other bracket portion 14 of the seismic isolation member 10 is fitted into a counter boring formed on the second coupling plate 30 and both of them are then fixed to each other, thus making it possible to fix more strongly the seismic isolation member 10 to the second coupling plate 30. Further, a part of the force generated on the seismic isolation member 10 can be directly transferred to the first coupling plate 20 by bearing pressure acting on a contact surface between the bracket portion and the counter boring, thereby reducing the force retained by the bolt 40. As a result, the bolt 40 can be reduced in diameter, or the number of the bolts 40 can be decreased.

FIG. 8 is a perspective view showing a second exemplified variation of a method for fixing the seismic isolation member 10 to the first coupling plate 20 (or the second coupling plate 30) in the seismic isolation apparatus 1. In the second exemplified variation, a U-shaped auxiliary member 23 is fixed by welding or other means to the side face of the first coupling plate 20 to which the seismic isolation member 10 is fixed. A recess 24 corresponding to the counter boring 22 of the first exemplified variation is formed by the side face inside the auxiliary member 23 and the side face of the first coupling plate 20 exposed so as to be surrounded by the side face inside the auxiliary member 23. Then, one bracket portion 13 of the seismic isolation member 10 is fitted into the recess 24 and fixed to the first coupling plate 20 via the bolt 40. In addition, although not illustrated, the bracket portion 14 disposed at the other end 12 of the seismic isolation member 10 is also fitted into a recess formed on the second coupling plate 30 and fixed to the second coupling plate 30 via the bolt 40.

In the above-described seismic isolation apparatus 1 as well, the seismic isolation member 10 can be fixed more strongly to the first coupling plate 20 and to the second coupling plate 30. Further, the force retained by the bolt 40 is reduced, and similar effects as described above can be attained accordingly.

Incidentally, in the above embodiment, only the X direction in FIG. 2 (the two-way (positive/negative) direction) is assumed as a direction of vibrations of the upper section of the structure, and seismic isolation members are placed along this direction. However, as shown in FIG. 9 and FIG. 10, as a direction of vibrations of the upper section of the structure, a plurality of directions, for example, the X direction (the two-way (positive/negative) direction) and Y direction (the two-way (positive/negative) direction) orthogonal to the X direction may be assumed. More specifically, the seismic isolation apparatus 101 shown in FIG. 9 and FIG. 10 is provided with eight seismic isolation members 10, a first coupling plate 120 to which one end 11 of each seismic isolation member 10 is fixed, and a second coupling plate 130 to which the other end 12 of each seismic isolation member 10 is fixed.

The first coupling plate 120 is a rectangular-shaped steel plate uniform in thickness, and one end 11 of each seismic isolation member 10 is fixed to the upper face via a bolt 40. A bolt hole (not illustrated) into which the bolt 40 is screwed is formed on the upper face of the first coupling plate 120. A plurality of stud bolts 21 are installed upright on the lower face of the first coupling plate 120.

The second coupling plate 130 is also a rectangular shaped steel plate uniform in thickness, and the other end 12 of each seismic isolation member 10 is fixed to the lower face via a bolt 40. A bolt hole (not illustrated) into which the bolt 40 is screwed is formed on the lower face of the second coupling plate 130. A plurality of stud bolts 31 are installed upright on the upper face of the second coupling plate 30.

Of eight seismic isolation members 10, two seismic isolation members 10C are placed at equal intervals along a side 120 a of the first coupling plate 120 and also oriented in a direction orthogonal to the side 120 a, by which the other end 11 is fixed to the upper face of the first coupling plate 20 via the bolt 40. Further, these two seismic isolation members 10C are placed at equal intervals along a side 130 a of the second coupling plate 130 and also oriented in a direction orthogonal to the side 130 a, by which the other end 12 is fixed to the lower face of the second coupling plate 130 via the bolt 40.

Of eight seismic isolation members 10, two other seismic isolation members 10D different from the above two members are placed at equal intervals along a side 120 b adjacent to the side 120 a to which the seismic isolation members 10C are fixed, and also oriented in a direction orthogonal to the side 120 b, by which one end 11 is fixed to the upper face of the first coupling plate 120 via the bolt 40. Further, these two seismic isolation members 10D are placed at equal intervals along a side 130 b adjacent to the side 130 a to which the seismic isolation members 10C are fixed, and also oriented in a direction orthogonal to the side 130 b, by which the other end 12 is fixed to the lower face of the second coupling plate 130 via the bolt 40.

Of eight seismic isolation members 10, two other seismic isolation members 10E different from the above other members are placed at equal intervals along a side 120 c adjacent to the side 120 b to which the seismic isolation members 10D are fixed, and also oriented in a direction orthogonal to the side 120 c, by which one end 11 is fixed to the upper face of the first coupling plate 120 via the bolt 40. Further, these two seismic isolation members 10E are placed at equal intervals along a side 130 c adjacent to the side 130 b to which the seismic isolation members 10D are fixed, and also oriented in a direction orthogonal to the side 130 c, by which the other end 12 is fixed to the lower face of the second coupling plate 130 via the bolt 40.

Of eight seismic isolation members 10, the remaining two seismic isolation members 10F are placed at equal intervals along a side 120 d adjacent to the side 120 c to which the seismic isolation members 10E are fixed, and also oriented in a direction orthogonal to the side 120 d, by which one end 11 is fixed to the upper face of the first coupling plate 120 via the bolt 40. Further, these two seismic isolation members 10F are placed at equal intervals along a side 130 d adjacent to the side 130 c to which the seismic isolation members 10E are fixed, and also oriented in a direction orthogonal to the side 130 d, by which the other end 12 is fixed to the lower face of the second coupling plate 130 via the bolt 40.

These two seismic isolation members 10C and the other two seismic isolation members 10E are fixed to the first coupling plate 120 and the second coupling plate 130. The seismic isolation members 10C are arranged so that curved portions of the seismic isolation members 10C are projected from between the first coupling plate 120 and the second coupling plate 130 in a direction (that is, in a positive direction indicated by the two-headed arrow X in FIG. 10). The seismic isolation members 10E are arranged so that curved portions of the seismic isolation members 10E are projected from between the first coupling plate 120 and the second coupling plate 130 in a direction opposite to the direction of the seismic isolation members 10C (that is, in a negative direction indicated by the two-headed arrow X in FIG. 10).

Further, these two seismic isolation members 10D and the other two seismic isolation members 10F are also fixed to the first coupling plate 120 and the second coupling plate 130. The seismic isolation members 10D are arranged so that curved portions of the seismic isolation members 10D are projected from between the first coupling plate 120 and the second coupling plate 130 in a direction (that is, in a positive direction indicated by the two-headed arrow Y in FIG. 10). The seismic isolation members 10F are arranged so that curved portions of the seismic isolation members 10F are projected from between the first coupling plate 120 and the second coupling plate 130 in a direction opposite to the direction of the seismic isolation members 10D (that is, in a negative direction indicated by the two-headed arrow Y in FIG. 10).

The first coupling plate 120 and the second coupling plate 130 are placed in such a manner that all four sides are in alignment with each other when viewed from above.

According to the seismic isolation apparatus 101, a direction in which vibrations are incoming is assumed previously, and the seismic isolation members 10 are placed so as to be set along the assumed two directions (the direction indicated by the two-headed arrow X and the direction indicated by the two-headed arrow Y in FIG. 10), thus making it possible to effectively damp the vibrations of the upper section which are generated in the assumed two directions. In other words, since it is not assumed that energy is incoming to the upper section from all directions but assumed that the energy is incoming only from specific directions, there is no necessity for making a detailed evaluation in designing the seismic isolation members 10, unlike a conventional case. Further, since no particular restrictions are imposed on the shape of the seismic isolation member 10, there is no necessity for raising the machining accuracy of the seismic isolation member 10 to the extent of a conventional seismic isolation member.

Therefore, production efficiency of the seismic isolation apparatus 101 can be raised both at the design stage and at the manufacturing stage, thus resulting in a lower manufacturing cost of the seismic isolation apparatus 1.

A description has been so far given of preferred embodiments of the present invention, to which the present invention shall not be, however, limited. The present invention may be subjected to addition, omission and replacement of the constitution and other modifications within a scope not departing from the gist of the present invention. The present invention shall not be limited by the above description but will be limited only by the scope of the attached claims.

For example, in the above embodiment, the seismic isolation apparatus is disposed on the lower section and then fixed to the lower section. Subsequently, the upper section is disposed on the seismic isolation apparatus, and the seismic isolation apparatus is fixed to the upper section. However, the method for installing the seismic isolation apparatus of the present invention may only include a step of disposing the seismic isolation apparatus on the lower section so that the seismic isolation members are set along a previously assumed direction of vibrations of the upper section to the lower section, a step of fixing the seismic isolation apparatus to the lower section, a step of disposing the upper section on the seismic isolation apparatus, and a step of fixing the seismic isolation apparatus to the upper section. Thus, the order of executing each of the above steps shall not be limited to the above-described order.

Further, the seismic isolation apparatus of the present invention is not only placed between a foundation (a lower section) and a building frame (an upper section) in structures such as buildings, bridges, elevated roads and elevated railways but also may be placed between members which constitute the above structures. The seismic isolation apparatus may be placed, for example, between a floor slab constituting a building and a deck slab placed on the floor slab. In this example, the seismic isolation apparatus absorbs the energy acting on the deck slab, instead of the energy acting on the building frame of the structure. Similarly, it may also be placed between a bridge pier constituting a bridge and a bridge girder placed on the bridge pier.

INDUSTRIAL APPLICABILITY

The present invention relates to a seismic isolation apparatus for damping vibrations of an upper section of a structure with respect to a lower section of the structure including a plurality of U-shaped seismic isolation members, a first coupling plate to which one end of the seismic isolation member is fixed, and a second coupling plate to which the other end of the seismic isolation member is fixed. Some of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a predetermined direction. The other of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a direction opposed to the predetermined direction.

According to the present invention, production efficiency of the seismic isolation apparatus can be raised both at the design stage and at the manufacturing stage, thus resulting in a lower manufacturing cost of the seismic isolation apparatus. 

1. A seismic isolation apparatus for damping vibrations of an upper section of a structure with respect to a lower section of the structure, the seismic isolation apparatus comprising: a plurality of U-shaped seismic isolation members; a first coupling plate to which one end of the seismic isolation member is fixed; and a second coupling plate to which the other end of the seismic isolation member is fixed, wherein some of the plurality of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a predetermined direction, and the other of the plurality of the seismic isolation members are placed between the first coupling plate and the second coupling plate in a direction opposed to the predetermined direction.
 2. The seismic isolation apparatus according to claim 1, wherein both ends of the seismic isolation member are fixed with bolts respectively to the first coupling plate and the second coupling plate.
 3. The seismic isolation apparatus according to claim 2, wherein one bolt is disposed at a portion of fixing one end of the seismic isolation member to the first coupling plate, and the other bolt is disposed at a portion of fixing the other end of the seismic isolation member to the second coupling plate.
 4. The seismic isolation apparatus according to claim 2, wherein a plurality of the bolts are disposed at a portion of fixing one end of the seismic isolation member to the first coupling plate, and the other bolts are disposed at a portion of fixing the other end of the seismic isolation member to the second coupling plate.
 5. The seismic isolation apparatus according to claim 1, wherein both ends of the seismic isolation member are welded respectively to the first coupling plate and the second coupling plate.
 6. The seismic isolation apparatus according to claim 1, wherein recesses into which one end or the other end of the seismic isolation member is fitted are formed respectively on the first coupling plate and the second coupling plate, and both ends of the seismic isolation member are fitted respectively into the recesses and thereafter fixed to the first coupling plate and the second coupling plate.
 7. The seismic isolation apparatus according to claim 1, further comprising an isolator having metal plates and plate-shaped elastic bodies alternately stacked, wherein the isolator is placed between the upper section and the lower section.
 8. A method for installing a seismic isolation apparatus on a lower section and an upper section of a structure, the seismic isolation apparatus having a first coupling plate to be fixed to the lower section, a second coupling plate to be fixed to the upper section opposing the lower section, and a plurality of seismic isolation members fixed respectively to the first coupling plate and the second coupling plate so as to be placed between the first coupling plate and the second coupling plate toward a predetermined direction and a direction opposing the predetermined direction, the method for installing the seismic isolation apparatus comprising the steps of: disposing the seismic isolation apparatus on the lower section so that the seismic isolation members are set along a previously assumed direction of vibrations of the upper section to the lower section; fixing the seismic isolation apparatus to the lower section; disposing the upper section on the seismic isolation apparatus; and fixing the seismic isolation apparatus to the upper section.
 9. A seismic isolation member placed between an upper section and a lower section, thereby damping the vibrations of the upper section to the lower section which are generated in a previously assumed direction by its own plastic deformation, wherein the seismic isolation member being formed in a U shape and placed between the upper section and the lower section along the previously assumed direction of vibrations, one end of the seismic isolation member is fixed to the lower section and the other end of the seismic isolation member is fixed to the upper section. 